The present invention relates to an electronic still single-lens reflex camera having an image sensor which subjects the image of an object to photoelectric conversion to obtain an electrical signal, and the electrical signal thus obtained is recorded on a magnetic recording medium by a magnetic recording head. More particularly, the invention relates to a tracking device for moving the recording head radially of the recording medium.
In an electronic camera, an image senor such as a solid-state image pickup element is used to obtain an electrical signal indicative of the brightness of the image of an object, and the electrical signal thus obtained is stored on a magnetic disk. Because the electronic camera employs an image sensor instead of film, in the electronic camera, the essential components of the camera other than the image sensor may be the same as those of a conventional film camera using film such as a still single-lens reflex camera. That is, the photometric device, the viewfinder optical system, the quick return mirror, the shutter and the lens stop of the still single-lens reflex camera can be used without modification to control exposure.
As mentioned above, in an electronic still single-lens reflex camera, the output electrical signal of the image sensor is processed and recorded and a recording medium, namely, a recording disk. A magnetic recording head is used to record the electrical signal on the recording disk. After one image signal has been recorded, the magnetic recording head must be moved radially of the magnetic disk (hereinafter referred to as "tracking") before the next image signal is recorded to then confront a new magnetic recording region on the surface of the magnetic disk. In other words, in an electronic camera, after one picture has been taken upon depressing the shutter button and recorded on the recording disk, tracking must be carried out before the next picture is taken. In a conventional electronic still single-lens reflex camera, a special drive source such as a pulse motor or servo motor is employed for the tracking of the recording head. Therefore, the camera suffers from difficulties that the manufacturing costs is high and the construction is intricate. Furthermore, the power consumption is large.